The passage mainly discusses______.A．why the change of meat-eating habit matters muchB．how

The passage mainly discusses______.

A．why the change of meat-eating habit matters much

B．how the British"s meaty habit had gradually emerged

C．when the British people began to prefer meaty diet

D．what meaty custom means to a truculent nation

请帮忙给出正确答案和分析，谢谢！